Generally, as illustrated in FIG. 1, a semiconductor die 100 can be connected to other dies or devices through bumps 101. These bumps 101 are normally connected to the semiconductor die 100 by layers of conductive material collectively known as under bump metallization (UBM) 103 that extend through a dielectric layer 111. The UBM 103 provides for a connection between the bump 101 and a contact pad 105 in order to electrically connect the bump 101 to the metal layers 107 and interconnects 109 formed within the semiconductor die 100.
However, while the contact pad 105, metal layers 107 and interconnects 109 are relatively small in size, the bump 101 and its corresponding UBM 103 are much, much larger. Accordingly, the UBM 103 has a much larger footprint on the surface of the die 100 than is required by the connection to the underlying metal layers 107 and interconnects 109. As devices are further scaled down, this large footprint on the surface of the semiconductor die 100 becomes even more of a liability, as multiple UMBs 103 compete for valuable real estate with other features such as trace lines on the surface of the die 100.
Accordingly, what is needed is a UMB and TSV combination that takes up less real estate on the surface of a semiconductor die, and also reduces or eliminates the competition between the UMBs and trace lines on the surface of a semiconductor die.